Gun mounting mechanism



F. y. HART ETAL GUN MOUNTING MECHANISM Filed May 12, 1942 4 Sheets-Sheet 1 Oct. s, 1946. F. v. HARf Em. I 2,409,041

GUN MOUNTING MECHANISM I Filed May 12, 1942 4 Sheets-Sheet 2 Get 8, 1946. F. v. HART ETAL 2,409,041

7 GUN MOUNTING MECHANISM r Filed May 12, 1942 4 SheetS-Sheet 3 Oct. 8, 1946. s v, HART r 2,409,041

GUN MOUNTING MECHANISM Filed May 12, 1942 4 Shets-Sheet 4 Z96 3/5 iii? 24 2a? I-HTIEF'TIV i E r Patented Get. 8, 1946 GUN MOUNTING IWECHANISM Fred V. Hart, Lynn, and Lambert S. Linderoth,

J12, Marblehead, Mass, assignors, by mesne assignments, to the United States of America, as represented by the Secretary of War Application May 12, 1942, Serial No. 442,688

This invention relates to remote control for power-operated devices and is herein shown as embodied in an arrangement in which it is desired to have the movements of the device correspond to the movements of a control member. The invention will be herein described in its application to the training of a gun but it will be understood that, broadly, it is equally adapted to remote control of other devices, such as moving tools or the like in shoe machinery.

An object of the invention is to provide an improved remote control mechanism for a device capable of movement in a plurality of paths, as in planes normal to one another. The direction, extent, and speed of movement of the device to be controlled will correspond exactly or correspond in a predetermined ratio with the direction, extent, and speed of movement of the opcrater-controlled member, to the end that an operator who has been accustomed manually to control the device in its various movements will readily eiiect a corresponding control by similar movements of a remotely located control member.

Guns mounted upon airplanes are usually supported for substantially universal movement within a limited range as, for example, by pivotally supporting the guns for tilting movement about one axis to control the elevation and for swinging movement about an axis normal to the first to control the deflection or azimuth. The space in which said guns are mounted is cramped and, usually, adequate armor protection for the operator cannot be provided adjacent to the guns. It is well understood also that the force'required to hold such a gun against the pressure of the air stream is very considerable and that it thus interferes with the speed with which such gun may be trained and the accuracy with which it may be held in the desired position.

A more specific object of the invention is to provide a remotely located control handle mounted for substantially universal movement in a protected portion of the airplane and to connect that control handle to a similarly mounted gun by power-operated apparatus including a followup mechanism connected directly to the movable device, such as the gun, to the end that the direction, speed and extent of movement of the device shall correspond to the direction, speed and extent of movement of the control member.

5 Claims. (CI. 89-41) In the case of machine guns, for example, these the gun by movements of the handle which correspond exactly in direction or angularity to those of the gun and correspond in a predetermined ratio with the speed and xtent of movement of the gun. Furthermore, to avoid the necessity for the operator to return the control handle to a zero or neutral position after every movement of the gun, follow-up mechanisms have been provided sothat the stopping of the handle is effective immediately to stop the movement of the gun. Furthermore, if an operator moves the handle quickly, the gun moves quickly with a corresponding speed. The follow-up mechanism positioned between the control member and'the power-operated mechanism is arranged to operate without overthrow or inaccuracy by directly connecting the follow-up to the movable part of the power-operated mechanism and hence to the gun itself. Another part of the follow-up mechanism is connected directly to the control handle and the connections are arranged to have opposite efiects, to the end that the gun is brought to a stop when the operator-controlled member is stopped.

In the illustrated apparatus, fluid-pressure motors are provided for causing the movements of the gun, and these are controlled by balanced valves, so that, once the gun is positioned, it is held automatically in that position without effort on the part of the operator. The valves have movable members which are directly operated by follow-up levers having dual fulcrums one of which is directly connected to and responds to the movements of the control member while the other is directly connected to the gun. These motors and valves are located closely adjacent to the gun, while the connections between the follow-up levers and the control member enable remote location of the control member. As herein illustrated, these connections are made by means of Bowden wires which are flexible enough to be carried around any necessary corners and are stiff enough to transmit the force needed to operate the valves.

Preferably, a sighting device is provided which is als'olocated remotely from the gun and which corresponding alinement.

These and other features of the invention will best be understood from a consideration of the following description taken in connection with the accompanying drawings, inwhich Fig. 1 is a vertical section taken longitudinally of the end of'a fuselage, showing in side eleing toward the rear of the guns and with the guns themselves shown diagrammatically as if in section;

Fig. is a horizontal section on broken line V--V of Fig. 4;

Fig. 6 is a vertical section through the gunelevating motor taken on the lin VI-VI of Fig; 4-.

Fig. 7 is a plan view of the gun supports, showing the motor for swinging the guns laterally and illustrating a portion of the links connecting the gun to the sight;

Fig. 8 is a detail view of a portion of the connection between the linkage and the sight support and taken below a partition in the fuselage shown in Fig. 1; I

Fig. 9 is a horizontal section on the line IXIX of Fig. 4 and looking down upon the control valves;

Fig. 10 isv an enlarged vertical section through the control valve shown at the right of Fig. 9

Fig. 11 is an elevation of the support for the sight and is taken from the left in Fig. 1;

Fig; 12 is a view similar to Fig. 1 but showing an alternative arrangement in which the control handles are positioned near the sight;

Fig. 13 is an elevation showing the modified gun sight and control handles and taken from the left in Fig. 12;

Fig. 14 is a horizontal section on the line XIVXIV of Fig. 13; and

Fig. 15 is a detail horizontal section on the line XVXV of Fig. 12.

One opportunity for the utilization of the control apparatus to be described isfound in airplanes where, for example, a gun compartment I0 is formed inside a section of the fuselage l2 as, for example, at the tail of an airplane where the twin guns i4 and I6, shown here in outline as being of the machine-gun type, are carried between partition plates l8 and 26-with the'guns pointed rearwardly through a port 22 in any direction within a sixty-degree cone for'each gun. Inasmuch as the skin of the fuselage'provides no substantial protection against gun fire, an operators compartment has been divided off by a partition 24 ofarmor plate in which, for convenience, there is a hinged door 26 to be utilized in supplying ammunition to the gun or for any necessary repair work. The. head of the gunner will be within a bulge 28 of the fuselage which is provided with suitable windows 36 and, in this portion of the fuselage, there is provided a gun sight 32 of any suitable type but herein shown in outline as a standard reflex sight having a casing 34 and an aiming device utilizing'a cross-hair image 36 (Fig. 11). The pointing of the gun is eifected by means of dual control handles 36 universally supported upon a bracket ill which is fastened to the under side of the armor partition 24.

The guns l4 and I6 are each'provided with side rods 42 upon which there'are clamped arms 44 (see also Figs. 4 and 7) which extend for- Wardly to provide fulcrums 4'6 and rearwardly to provide pivots 48. The fulcrums 46 which permit the guns to swing about a horizontal axis are joined to suitable projections 56 upon pairs of vertical side plates 52. The side plates 52 are bent outwardly (Fig. 4) for compactness of design and the lower ends of each pair of the plates are bolted to a W-shaped member 54, shown at the right in Fig. 5. At their upper ends, the plates 52are bolted to T-shaped caps 56 and 5?, shown in elevation at the top of Fig. 4 and in plan in Fig. 7. The head portion of the T- shaped member 56 has a stud 58 (Fig. 7) in a ballbearing'about an axis normal to a cross plate Ell which is carried on the under side of the partition [8 shown in Fig. 1. A rod 2l6 attached to the cap 51 is similarly pivoted in. plate 60. At the lower ends of these gun-carrying plates 52, the W-shaped pieces 54 (Fig. 4) are pinned to upright rods 62, alined with stud 58 and rod 2l6, respectively. The lower end of each of these rods 62 is carried by ball bearings on a base plate 64 which is secured to the partition 20 of the fuselage. The T-shaped caps 56 and 51 at the top of the gun supports are interconnected by a link 66 (Fig. 7) so that they maintain parallelism, and the swinging of the gun mounts in azimuth about each of their respective axes is effected by power through the action of fluidpressure means herein illustrated as a hydraulic motor iii in which there is a piston 12 having a piston rod 13 connected by a link M, at the left, to. the left T-shaped member 55.

Tilting of th guns in elevation about the horizontal fulcrums 46 is effected by another hydraulic motor 86 (Figs. 4, 5 and 6) secured to the base plate 64. The piston 82 of this motor is joined by a piston rod 84 to a slide 86 having side fins 88 and at its lower end 90 encircling the outside of the cylinder of the motor 80. The lower end '90 is grooved to receive side plates 92 and 94 (Fig. 5) between the opposite ends of which are split blocks 96 which rotatably receive the sleeve-like lower portions 98 of travelers I00 each slidable upon one of the rods 62 and prevented from rotation with respect thereto by a spline I62. The travelers lllfi are joined by links I64 to the pivots 48 upon the arms 44 which are clamped to the rods 42 at the sides of the guns. Operation of the motor is therefore effective to tilt the guns about their horizontal fulcrums 46 so as to elevate or depress the muzzles without interfering with their lateral movement. It will be seen, therefore, that, since the lateral movements ina'horizontal plane, for example, are independent of the up-and-down movements of the guns in vertical planes normal to the plane of its, lateral movement, it is only necessary to control the admission of fluid to the motors l6 and 80 in order to be able to point. the guns in any one of an infinite number of directions. In so doing, it is convenient to consider the movement of a point on the back end of the gun, for example-,and to note that the angular movement of a point onthe control handle is duplicated by the point on the gun, while the speed and extent of movement of the gun corresponds in a predetermined ratio, to the speed and extent of movement of the. handle.

The pointing of the guns was formerly effected by grasping handles H6 fastened directly to the guns themselves to move them manually but, when the guns are mounted as they are upon airplanes, the air currents along the fuselage tend constantly to divert the guns. from their intended directions, and the physical labor of moving and aiming them is very considerable.

'ment around a vertical axis.

Advantageously, therefore, the control handles 38 are mounted for movement on thebracket 40 so as to correspond to the movements of the handles IIO on the guns themselves. To this end, the handles are clamped to a T-shaped car-. rier II2 (Figs. 2 and 3) which is pivotally mounted at II4 between arms II6 xtended upwardly from a rotor IIB having a depending sleeve portion pivoted in the bracket 40 for move- The handle carrier I I2 is provided with a notched portion I20 which cooperates with a stop pin I22 to keep up and down movements of the guns within the cones of fire. Similarly, the rotor IIB has a notched portion I24 (Fig. 2) corresponding with a stop pin I26 similarly to limit lateral swinging of the handles and hence of the guns. On the carrier II: is an arm I28 joined to a vertical rod I30 the lower end of which is connected to a bell" crank I32 (Fig. 1) pivoted on the bracket 40. The other arm of the bell crank is joined to a Bowden wire I34 leading to a bell crank I36 pivoted upon the casing of a control-valve mechanism I40 supported on a bracket I4I attached to the base plate 64. This valve mechanism I40 controls the motor 80 by which elevational movements of the guns are produced. The rotor II8 associated with the control handle has an arm I42 (Fig. 2) to which there is joined a Bowden wire I44 leading through a guide I46 on the bracket 40 and another guide I48 (Fig. 9) to a bell crank I49 pivotally connected to the casing of a control-valvemechanism I50. The valve mechanism I50 is attached to the base plate 64 (Figs. 4 and 9) and controls movements of the guns in azimuth.

The control-valve mechanisms are identical in construction and operation and accordingly only one of them is herein illustrated and described in detail. To facilitate this description, a few parts of the valve mechanism I40, which parts are better shown and are like the corresponding parts of the valve mechanism I50, have been given numerals like those used in describing parts of the mechanism I50 but with a prime added to each number. Examples of such parts are the piston I65 and a block I68 notched at I18 to surround a fixed rod I80 and having pins I69 by which it is pivotally mounted in a forked follow-up lever I12. This lever I12 is pivoted at one end to a link I14 joined by a pin I15 to the fins 88 of the slide moved by the motor 00 to produce movements of the guns in elevation. The balanced-valve mechanism I50 by means of which the right and left movements of the gun to change its azimuth may be effected is shown in Figs. 9 and 10. The casing is provided with a port I52 which communicates by means of a pipe I54 with the left-hand end (Figs. 4 and '1) of the cylinder of the motor so that, upon the admission of fluid through this pipe to the cylinder, the piston 12 shown in Fig. 7, will be moved to the right and the rear ends of the guns I4 and I6 at the lower end of Fig. '7 will be moved to the right. By means of another port I56 and a connecting pipe I58 joined to the right- -hand end of the motor 10, movement of the rear ends of the guns to the left may be effected by the action of the pressure fluid on the opposite end of the piston 12. It will be recalled that the piston 12 is connected by a link 14 with the elongated portion of the T-shaped member 56 at the top of the gun carrier and that the two guns are connected by a parallel linkage including a link 66 (Fig. 7) so that they are always parallel.

6 In the casing of the valve I50 is a fixed sleeve I60 provided with external annular grooves connected by a series of openings, such as that shown at I62, to the interior of the valve in which there is a slidable valve member I64 having a stem I65 and provided at each end with a flexible packing I66 such as is shown in section at the right end and having at its left end a guide block I68 which is similar in shape to the block I68 (shown at the left of Fig. 9) and has pivot pins I69 like the pins I69 in Fig. 9. These pins I69 are received in holes, slightly larger than the pins, in the side arms I10 of a forked lever I12 which acts as a control member and is joined at its lower end by a link I14 to an arm I16 clamped to one of the vertical rods 62 which turns in its ball-bearing base whenever the guns are swung laterally. In that block I68 is a notch (not shown), such as that shown at I165 at the left of Fig. 9, in the block I68. The notch of the block I60 surrounds a fixed rod I extending out from the valve casing and having limit nuts I82 to control its range of movement. The other end of the lever I12 is connected by a link I84 to an end of the bell crank I49 to which there are transmitted the right-and-left movements of the handles 38 through the Bowden wire I44. The valve member I64 has a series of piston: like enlargements or lands I61 so that fluid under pressure delivered to the valve casing through a port I will be transmitted to either the right or the left end ofthe cylinder of the motor 10 as the handles 38 are moved. The enlargements I61 are of equal diameter so that the valve is balanced and the widths of the lands are almost exactly equal to the diameters of the coacting openings, such as that at I62. Hence, only a minute movement of the valve member I64 is needed to open the valve, thus making the apparatus instantly responsive to movements of the control handles 38. The annular grooves in the valve sleeve I60 adjacent to the ends thereof are interconnected by a longitudinal passage I94 so that the oil, in that end of the cylinder 10 toward which the piston 12 is moving, can be exhausted through a port I92, regardless of which way the piston 12 is moved.

There is provided, therefore, by the control member I12 which is arranged to operate the valve I50 and which is oppositely connected to the work and to the operator control, a followup mechanism the action of which is automatic. The action of this follow-up mechanism moreover is continuous in that it effects an instant response to the movements of the control handle thereby avoiding any lag or hunting movements of the gun and insuring the duplication by the gun of the position of the control handle.

A movement of the gun is imediately transmitted to the sight 32 by reason of mechanical connections extending between the two. To this end, the sight is attached to hangers 200 (Fig. 11) pivoted at 202 between the upstanding arms of a stirrup-like support 204, which is riveted upon the upper end of a vertical rod 206. The lower end of this rod is rotatably supported in a bearing 208 (Figs. 1 and 8) secured to the partition 24, and turning movement about a vertical axis, to accord with the lateral deflection in azimuth of the gun, is imparted to this rod by means of a lever 2I0 (Figs. '7 and 8) attached thereto and joined by a connecting rod M2 to a lever 2I4 secured to the top of the vertical rod 2I6, which is fastened to the cap 51 at the top of one of the gun supports (Fig. 4).

Furthermore, it is necessary .to tilt the sight 32 about thepivots 292 to a degreematching the up-and-down tilting of the guns, and thisis done by means of a lever 22% (Fig. 1) fulcrumed at 222 on the inner side of the fuselage l2. The lever 22!] has its outer end 224 forked (Figs. 4 and '7) and slidable in the grooves of a block 226 mounted on the upper end of a rod 228. This rod 228 slides in a suitable bearing in the upper plate 60 of the gun carrier and is given a reduced movement proportionate to the movement of the gun-elevating slide 86 by means of a lever 230 fulcrumed at one end upon brackets 2'32 (Figs... 1 and 4) depending from the plate 651, and pivoted at the other end to a connecting rod 234 which extends down to and is fastened to the slide 86. At its inner end, the lever 220 is forked at 235 (Fig. 7) and has a sliding and pivotal connection 238 (Fig. 11) with a block member 249 which is slidably mounted on the supporting rod 205 and has a spool portion 242 receiving a notched yoke 244 (see also Fig. '7). The ends of this yoke are joined by flat links 246 (Fig. 1) to rigid arms 24:; which are integral with the hangers 209. The lower ends of these links 2 36 are connected by parallel links 250 to downwardly directed arms 252 which are a part of the stirruplike hanger or support 204 (Fig. 11) The hanger or support 264 thus forms a part of a parallel linkage, including the links 246, the arms 2% and the links 258. Up-and-down movements of the gun-tilting slide 68 are therefore communicated through the reducing lever 230 to the long lever 220 and thence to the parallel linkage which is joined to the yoke 24%. Themechanism just described is, therefore, capable of turning and tilting the sight 32 so that it is always parallel to the longitudinal axes of the guns l4 and H and gives the gunner an accurate indication of the direction in which they are pointed.

In a modified form of the invention illustrated in Figs. 12 to 15, inclusive, the mechanism for turning and tilting the gun is exactly the same as in the arrangement already described, but the control handles 25B are here mounted on arms 262 integral With hangers 2513 for the gun sight 32. These hangers also have forwardly extending arms 268 for a purpose similar to that of the rigid arms 243. The hangers 264 are pivotal-1y mounted at its at the upper ends of the arms of a supporting stirrup 2Y8 which is fastened to the top of a vertical rod 272 and the latter is rotatable in a bearing 2M attached to the underside of the partition 24, and has at its lower end an arm 216 (Fig. 15) joined by a link 278 to a lever 285 which is pivoted upon the lower end of a bracket 282 attached to the partition 2%. At the other end of the lever 280, there is attached a Bowden wire 284 leading to the valve I59 which controls the lateral swinging movements of the guns as the gun supports are turned by means of the power transmitted from the motor "50. An extension 236 of the bracket 282 provides a support for the sheath 2&2 of the Bowden wire 284. The stirrup 228 is provided with depending arms 290 joined by parallel links 292 to upright links 294, the lower ends of which are bolted to a yoke 296 (Fig. 14;) engaging the groove of a spool 25% (Figs. 12 and 13) slidable vertically on the rod 212. This spool is connected by links 3% to a forked lever 302 (Figs. 11 and 15), the other end of which is pivoted on the bracket 282- This forked lever 302 has a nub smite which is connected the upper end of a Bowden wire 3%, which controls'the valve M0 that determines the up-and-down movementsof the slide 86 for tilting the guns to elevate or depress them. An arm 3118 supports a sheath 310 for this Bowden wire. It will be noted that the yoke 298 (Fig. 14) is provided with a stop pin 3l2, which is adapted to be engaged by ears on a collar 314 secured to the upright sight-supporting rod 272. By this arrangement, the lateral turning of the sight and the handles 260 is limited to the range of movement, laterally, of the guns and supports. It follows that this modified mechanism brings the control handles 260 to a point beside the sight 32, and, by reason of the direct connection between the handles and the sight, causes substantially synchronous movements of the latter and the guns, as theBowden wires 284' and 306, by reason of their connections to the control valves l50 and M0, produce corresponding movements of the guns.

In the operation of the arrangement illustrated in Figs. 1 to 11, the gunner, grasping the control handles 38, will move them about the universal mounting provided on the bracket 40 and, by means of the control mechanism including the directly-connected follow-ups, will cause an immediate training of the guns in such a manner that the angular displacement of a point upon the rear end of a gun will correspond exactly to the movements of a point on the control handle. These movements will be compounded of vertical movements in planes normal to one another about the fulcrums M5 and of lateral swinging movements about the axis of a rod 62. The actual movement of a point on the rear end of the gun will therefore take place along any one of a plurality of paths in either direction. Since these movements are compounded of. movements produced in azimuth and movements produced in elevation, it will be sufficient to note the operation of either one of these devices. For example, if the control handle 38 is swung about its vertical axis, its movement will be transmitted through the Bowden wire I44 (Figs. 2 and 9) to the bell crank I49 which is directly connected by the link I84 to one end of the followup mechanism exemplified by the lever I12. This movement of one end of the lever H2 produced by the handle will be immediately transmitted to the valve 153 as the lever swings about the fulcrum provided by the link I14, and the movement transmitted to the valve will cause the flow of fluid under pressure to that end of the fluid motor 'Hl' (Fig. 7) which will cause a swinging movement in a horizontal plane, and in a direction corresponding to that of the handle movement, of the guns l4 and IB' about their vertical pivots 58 and 62' (Fig. 4) If the handle, as viewed in Fig. 2, is moved to the left, for example, the Bowden wire I41! will be pushed, causing the upper end of the lever H2, as viewed in plan in Fig. 9, to be moved to the right. This will shift the valve member I65 to the right, in Fig. 10, letting fluid under pressure fiow through the port I and thence through the connecting pipe !58 to the right end of the motor 10, thus causing the rear ends of the guns to be swung to the left. i

The speed of this movement will depend upon the degree of opening of the passage I56 by the valve member I64 and. this will depend upon the speed of movement of the control handle 33. Thus a quick movement of the handle will be accompanied by a quick operation of the motor 10', and it will be noted that this action takes place by reason of a direct connection of the control handle 33 to the valve member. Just as soon as the motor starts to move, thereby turning the guns, there will be a turning movement of the arm I16 (Fig. 9) clockwise in this particular instance, thereby reacting directly through the link I'M upon the follow-up lever I12 and tending to swing this lever about its pivotal con nection to the link I84 in a direction to draw the valve member I84 to the left so as again to shut off the supply of pressure fluid through the pipe [58 to the motor unless the operator is at the same time moving the hand lever 38 to the left to counteract this tendency to close the valve 464. In consequence of this arrangement, the operator is under no burden of returning the control handle to any initial position but moves it only where he would move it if he were operating the guns manually. The extent of movement of the guns accordingly corresponds, either exactly or in a predetermined ratio, to the movement of the control handle 38. The extent of the angular movement of the gun is the same as the extent of angular movement of the control handle. It has already been noted that the speed and direction of movement of the gun depend upon the speed and direction of movement of the control handle and, consequently, the direction, speed and extent of movement of the device are determined and controlled directly and continuously by the direction, speed and extent of movement of the control member, and, even though the control member 38 is remotely positioned from the device, here the guns, the gunner can with confidence initiate the firing of the guns at any time with the assuranc that there is no lag or hunting and that the guns occupy a position like that occupied by the control member. It will be observed that the sighting device 32 will be immediately and correspondingly moved to bring it into visual alinement with the target. By reason of the direct connections of the followup to the control handle and to the gun, the extent of movement of the gun and the speed of movement thereof will correspond in a predetermined ratio determined by the design of the follow-up lever to the speed and extent of movement of the control handle.

In the device illustrated in Figs. 12 to 15, inclusive, where the control handles are directly connected to the sighting device, any theoretical lag between the movements of the gun and the movements of the handle, so that the bringing of the sighting device into visual alinement with the target will slightly anticipate the movements of the gun, is so slight as to be substantially imperceptible to the operator.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. In a power operated mount for a gun, a pair of normally-vertical side plates embracing said gun and interconnected above and below said gun to form a frame, means pivoting said gun on and between said plates for elevation about a first normally-horizontal axis fixed relatively thereto, means mounting said frame for pivotal movement about a second normally-vertical axis and including a shaft aligned with said second axis and fixed to said frame, a traveler guided for translation only on and along said shaft, motor means connected to so translate said traveler,

10 and link means pivoted at one end of said gun on an axis parallel to and offset with respect to said first axis, and to said traveler at the other end, whereby operation of said power means pivots said gun in elevation.

2. In a power-operated mount for a gun, a pair of vertical side plates connected to form a frame embracing said gun, means pivoting said gun on and within said frame for elevation about a normally-horizontal first axis, means pivoting said frame for movement about a normally-vertical second axis and including a splined shaft aligned with said second axis and rigid with said frame, a traveler surrounding said shaft and engaging the spline thereof for translation only on and along'said shaft, a link pivoted to said traveler at one end and to said gun at the other end, upon an axis parallel to and offset from said first axis, a hydraulic motor comprising a cylinder, a piston and piston rod, having their axis parallel to and offset from said second axis, a guide mounted for translation on and along said cylinder, a rigid connection between said piston rod and guide, an arm fixed to said guide and extending adjacent said traveler, and a swivel connection between said arm and traveler, whereby reciprocation of said piston, rod, guide, arm and traveler, pivotally moves the gun in elevation.

3. The structure as in claim 2, said frame including a cap at the top thereof, a second hydraulic motor comprising a cylinder, piston and piston rod, adjacent said cap and having its axis normal to said second axis, and a link pivoted to said rod and to said cap, at a point off-set from said second axis.

l. In a power-operated mount for twin guns mounted side by side and adapted for training and elevation in synchronism, a pair of frames, each surrounding a respective gun, means mountmg each gun in its frame for elevation with respect thereto about a normally-horizontal first axis, means mounting each frame for movement about a normally-vertical second axis and including a pair of parallel shafts each co-axial with a respective second axis, a pair of travelers each mounted for translation only on and along a respective shaft, link means connecting each traveler with a respective gun, on pivot axes parallel to and offset fro-m said first axis, a first motor between and parallel with said shafts and including a cylinder, piston and piston rod, a guide mounted for translation on and along said cylinder and rigidly connected with said piston rod, and a member fixed to said guide and having oppositely projecting arms each swiveled to a respective one of said travelers, whereby on application of hydraulic pressure to said piston, said rod, member and travelers are reciprocated as a unit, to synchronously move said guns in elevation.

5. The structure as in claim 4, a link pivoted to said frames and connecting the same for movement in unison about said second axis, a second motor comprising a cylinder, piston and piston rod, with their axis normally horizontal, and a direct connection between said last-named piston rod and one of said frames, whereby operation of said second motorrotates said guns in unison about said second axis.

FRED V. HART. LAMBERT S. LINDEROTl-I, JR. 

